1. Field Of The Invention
This invention relates to apparatus for stripping an outer shield from an electrical cable, and more particularly, to a shield stripping apparatus having a cutting blade pivoted in a plane parallel to a longitudinal axis of the cable.
2. Description Of The Prior Art
Stripping the outer shield from an electrical cable without cutting the insulation on the internal wires therein is a procedure which is normally done by hand and results in high labor costs. One apparatus devised to provide longitudinal cutting of an external shield of an electrical cable is shown in U.S. Pat. No. 3,623,384 to Murphy which includes a cable receiving housing with a pivoted blade therein. The blade is spring loaded outwardly away from a central opening of the housing, and external pressure must be applied to the blade to keep it in a cutting position.
Another wire stripper which can cut longitudinally along a cable is disclosed in U.S. Pat. No. 4,117,749 to Economu. This apparatus includes a body with pivoted jaws which hold cutting blades therein. The jaws are springingly biased away from the cable, and thus also require external pressure thereon to maintain the blades in a cutting position.
While the Murphy and Economu apparatus allow longitudinal cuts along a cable, the requirement of external pressure may result in uneven cutting along the outer shield. Also, the internal wires within the outer shield are usually wound in a spiral or helix, and these prior apparatus are not well adapted for following the internal wires within the shield. Thus, there is a possibility of undesired cutting of the internal wires.
There is therefore a need for an apparatus which applies constant cutting pressure on an outer shield of a cable while allowing the blade to rotate to follow the internal wires as the cable is pulled therethrough, thus compensating for the spiral wind of the internal wires and lessening the likelihood of cutting the insulation on those wires. The present invention which includes a pivoted blade which is positively held in a cutting position, requiring no external pressure thereon, and which allows the cutting head to rotate as the cable is pulled therethrough provides a solution to these problems.